In U.S. Pat. No. 5,827,565 it is pointed out that most dogs enjoy chewing on a flavored object although preferences vary as to the hardness. Some dogs like to chew on very hard materials such as cow bones, wood, nylon, while others prefer softer chews such as polyurethane or rubber while still others favor freeze dried snacks. Some dogs, due to their age, may not be able to chew on very hard substances. Young dogs have insufficiently developed teeth, while old dogs may have diseased gums or may have lost some of their teeth.
Applicants' assignee, T.F.H. Publications Inc., has previously developed an edible dog chew that is wholly digestible, nutritious and maintains a texture or hardness which is individually adjustable by the application of heat to suit a wide variety of a dog's preferences or needs. Such dog chews utilize a mixture containing primarily casein and are described in U.S. Pat. Nos. 5,200,212 and 5,240,720.
In U.S. Pat. No. 5,827,565 owned by the common assignee of this Application there is disclosed a process for making a heat expandable dog chew comprised primarily of injection molding potato starch granules and an attractant. Attractants recited include chicken powder, liver powder, ham, turkey, beef and or fish. Natural vegetable additives such as spinach or carrots also may be added. The resultant mixture is molded under heat and pressure into a desired form, such as a dog bone. The dog bone so produced can be modified in texture or hardness by subsequent heating, preferably in a microwave oven.
In U.S. patent application Ser. No. 09/138,804, which is a continuation-in-part of U.S. Pat. No. 5,827,565, and which is owned by the common assignee of this Application, there is disclosed a dog chew having natural fruit flavor to increase the dog's appetite for such chew. Such fruit flavored dog chew may also include natural food coloring to enhance the attractiveness of the chew to the dog owner. The food coloring may also correspond to the fruit flavor, and the dog chew disclosed therein may also embody a breath sweetener for a dog such as mint, spearmint, peppermint or wintergreen and may also include parsley. The preferred form of such edible chew maintained the basic ingredient of a heat-expandable starch, such as potato starch. Fruit flavoring may be added to the granules of a mixture of potato starch, water and calcium carbonate along with natural fruit flavorings.
Attention is also directed to the following U.S. Patents and copending applications, commonly owned by the assignee herein: U.S. Pat. No. 5,476,069; U.S. patent application Ser. No. 08/923,070 filed Sep. 3, 1997 entitled "Vegetable Based Dog Chew" now U.S. Pat. No. 6,093,427; Ser. No. 08/738,423 filed Oct. 25, 1997 entitled "Edible Dog Chew" now U.S. Pat. No. 5,827,565; Ser. No. 08/784,834 filed Jan. 17, 1997 entitled "Carrot-Based Dog Chew" now U.S. Pat. No. 5,941,197; Ser. No. 08/888,611 filed Jul. 7, 1997 entitled "Vegetable Dog Chew" now abandoned; Ser. No. 09/114,872 filed Jul. 14, 1998 entitled "Heat Modifiable Edible Dog Chew" now U.S. Pat. No. 6,180,161; Ser. No. 09/138,804 filed Aug. 21, 1998 entitled "Improved Edible Dog Chew" now U.S. Pat No. 6,126,978; Ser. No. 09/116,070 filed Jul. 15, 1998 entitled "Wheat & Casein Dow Chew With Modifiable Texture" now U.S. Pat. No. 6,110,521; Ser. No. 09/116,555 filed Jul. 15, 1998 entitled "Heat Modifiable Peanut Dog Chew" now U.S. Pat. No. 6,093,441; Ser. No. 09/227,767 filed Jan. 8, 1999 entitled "Method of Molding Edible Starch" now U.S. Pat. No. 6,159,516. In addition to such patents and applications, attention is also directed to the art cited in said patents and applications, as such art relates to the field of molded starch products.
In addition, the prior art has recently grown considerably to include a variety of other disclosures directed at flavored pet products. For example, U.S. Pat. No. 5,786,383 entitled "Use of Valerian Plant and/or Root as a Scent-Attractant for Stimulating Canines and Felines". This patent discloses the use of the herb/plant Valerian in all of its forms whether whole or in part, for use in food product, in such a manner that the natural aroma emitted by the Valerian plant will act as a scent/attractant for dogs and cats.
U.S. Pat. Nos. 4,985,964 and 5,007,879 entitled "Dog Chew Processing Method" disclose methods for processing cattle hoofs for use as a dog chew product.
U.S. Pat. No. 5,149,550 entitled "Methods for Making Pet Chews" discloses that ligaments from cattle and other hoofstocks are rendered substantially free of fat and can be dried and hardened for use as a pet chew.
U.S. Pat. No. 5,407,661 entitled "Pet Chew Product Having Oral Care Properties" discloses an edible pet chew product having a flexible cellular matrix in which is contained cellulosic fibrous material such as corn cob fractions which are described as having a mechanical cleansing function when chewed by a pet.
U.S. Pat. No. 5,635,237 entitled "Method of Manufacturing Substantially Pure Rawhide Pet Products" discloses a chew of pure rawhide utilizing twin screw extrusion with multiple heating zones and interchangeable extrusion dies.
U.S. Pat. No. 5,711,254 entitled "Dog Chew Toy" discloses a chew toy for dogs formed of a length of composite rope having an inner core defined by strands of twisted threads of natural plant or synthetic fibers and a soft outer shell defined by a plurality of strands of soft cotton threads twisted about the inner core. The inner core is said to be less water absorbent than the outer shell to promote drying of the toy when wetted with dog saliva to inhibit bacteria growth.
U.S. Pat. No. 5,750,196 entitled "Process for Manufacturing Dog Chew Toys of Tire Sidewalls" discloses the use of a dye to cut toy bases from sidewalls recovered from used tires.
Other earlier examples of such products are disclosed in U.S. Pat. No. 3,871,334 to Axelrod (nylon substrate containing liquid flavor and odor components) and U.S. Pat. No. 4,711,773 to Axelrod (polyurethane toy containing aqueous-based flavor and odor components). U.S. Pat. Nos. 4,557,219 and 4,513,014 to Edwards disclose the use of flavorings in a molded polyurethane chew objects.
Accordingly, it is an object herein to improve further upon Applicants' earlier disclosures regarding animal chews, to form a biodegradable animal chew from a thermoplastic polyesteramide and starch. Furthermore, it is also an object of the present invention to form a biodegradable animal chew wherein the polyesteramide component is present in distinct domains dispersed within a continuous starch phase.